Date:   Tue, 7 Mar 2023 17:06:11 +0530
From:   Gautam Dawar <gautam.dawar@....com>
To:     <linux-net-drivers@....com>, <jasowang@...hat.com>,
        Edward Cree <ecree.xilinx@...il.com>,
        Martin Habets <habetsm.xilinx@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        "Jakub Kicinski" <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Richard Cochran <richardcochran@...il.com>,
        <linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>
CC:     <eperezma@...hat.com>, <harpreet.anand@....com>,
        <tanuj.kamde@....com>, <koushik.dutta@....com>,
        Gautam Dawar <gautam.dawar@....com>
Subject: [PATCH net-next v2 09/14] sfc: implement device status related vdpa config operations

vDPA config opertions to handle get/set device status and device
reset have been implemented. Also .suspend config operation is
implemented to support Live Migration.

Signed-off-by: Gautam Dawar <gautam.dawar@....com>
---
 drivers/net/ethernet/sfc/ef100_vdpa.c     |  16 +-
 drivers/net/ethernet/sfc/ef100_vdpa.h     |   2 +
 drivers/net/ethernet/sfc/ef100_vdpa_ops.c | 367 ++++++++++++++++++++--
 3 files changed, 355 insertions(+), 30 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef100_vdpa.c b/drivers/net/ethernet/sfc/ef100_vdpa.c
index c66e5aef69ea..4ba57827a6cd 100644
--- a/drivers/net/ethernet/sfc/ef100_vdpa.c
+++ b/drivers/net/ethernet/sfc/ef100_vdpa.c
@@ -68,9 +68,14 @@ static int vdpa_allocate_vis(struct efx_nic *efx, unsigned int *allocated_vis)
 
 static void ef100_vdpa_delete(struct efx_nic *efx)
 {
+	struct vdpa_device *vdpa_dev;
+
 	if (efx->vdpa_nic) {
+		vdpa_dev = &efx->vdpa_nic->vdpa_dev;
+		ef100_vdpa_reset(vdpa_dev);
+
 		/* replace with _vdpa_unregister_device later */
-		put_device(&efx->vdpa_nic->vdpa_dev.dev);
+		put_device(&vdpa_dev->dev);
 	}
 	efx_mcdi_free_vis(efx);
 }
@@ -171,6 +176,15 @@ static struct ef100_vdpa_nic *ef100_vdpa_create(struct efx_nic *efx,
 		}
 	}
 
+	rc = devm_add_action_or_reset(&efx->pci_dev->dev,
+				      ef100_vdpa_irq_vectors_free,
+				      efx->pci_dev);
+	if (rc) {
+		pci_err(efx->pci_dev,
+			"Failed adding devres for freeing irq vectors\n");
+		goto err_put_device;
+	}
+
 	rc = get_net_config(vdpa_nic);
 	if (rc)
 		goto err_put_device;
diff --git a/drivers/net/ethernet/sfc/ef100_vdpa.h b/drivers/net/ethernet/sfc/ef100_vdpa.h
index 348ca8a7404b..58791402e454 100644
--- a/drivers/net/ethernet/sfc/ef100_vdpa.h
+++ b/drivers/net/ethernet/sfc/ef100_vdpa.h
@@ -149,6 +149,8 @@ int ef100_vdpa_register_mgmtdev(struct efx_nic *efx);
 void ef100_vdpa_unregister_mgmtdev(struct efx_nic *efx);
 void ef100_vdpa_irq_vectors_free(void *data);
 int ef100_vdpa_init_vring(struct ef100_vdpa_nic *vdpa_nic, u16 idx);
+void ef100_vdpa_irq_vectors_free(void *data);
+int ef100_vdpa_reset(struct vdpa_device *vdev);
 
 static inline bool efx_vdpa_is_little_endian(struct ef100_vdpa_nic *vdpa_nic)
 {
diff --git a/drivers/net/ethernet/sfc/ef100_vdpa_ops.c b/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
index 0051c4c0e47c..95a2177f85a2 100644
--- a/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
+++ b/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
@@ -22,11 +22,6 @@ static struct ef100_vdpa_nic *get_vdpa_nic(struct vdpa_device *vdev)
 	return container_of(vdev, struct ef100_vdpa_nic, vdpa_dev);
 }
 
-void ef100_vdpa_irq_vectors_free(void *data)
-{
-	pci_free_irq_vectors(data);
-}
-
 static int create_vring_ctx(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
 {
 	struct efx_vring_ctx *vring_ctx;
@@ -52,14 +47,6 @@ static void delete_vring_ctx(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
 	vdpa_nic->vring[idx].vring_ctx = NULL;
 }
 
-static void reset_vring(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
-{
-	vdpa_nic->vring[idx].vring_type = EF100_VDPA_VQ_NTYPES;
-	vdpa_nic->vring[idx].vring_state = 0;
-	vdpa_nic->vring[idx].last_avail_idx = 0;
-	vdpa_nic->vring[idx].last_used_idx = 0;
-}
-
 int ef100_vdpa_init_vring(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
 {
 	u32 offset;
@@ -103,6 +90,236 @@ static bool is_qid_invalid(struct ef100_vdpa_nic *vdpa_nic, u16 idx,
 	return false;
 }
 
+static void irq_vring_fini(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
+{
+	struct ef100_vdpa_vring_info *vring = &vdpa_nic->vring[idx];
+	struct pci_dev *pci_dev = vdpa_nic->efx->pci_dev;
+
+	devm_free_irq(&pci_dev->dev, vring->irq, vring);
+	vring->irq = -EINVAL;
+}
+
+static irqreturn_t vring_intr_handler(int irq, void *arg)
+{
+	struct ef100_vdpa_vring_info *vring = arg;
+
+	if (vring->cb.callback)
+		return vring->cb.callback(vring->cb.private);
+
+	return IRQ_NONE;
+}
+
+static int ef100_vdpa_irq_vectors_alloc(struct pci_dev *pci_dev, u16 nvqs)
+{
+	int rc;
+
+	rc = pci_alloc_irq_vectors(pci_dev, nvqs, nvqs, PCI_IRQ_MSIX);
+	if (rc < 0)
+		pci_err(pci_dev,
+			"Failed to alloc %d IRQ vectors, err:%d\n", nvqs, rc);
+	return rc;
+}
+
+void ef100_vdpa_irq_vectors_free(void *data)
+{
+	pci_free_irq_vectors(data);
+}
+
+static int irq_vring_init(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
+{
+	struct ef100_vdpa_vring_info *vring = &vdpa_nic->vring[idx];
+	struct pci_dev *pci_dev = vdpa_nic->efx->pci_dev;
+	int irq;
+	int rc;
+
+	snprintf(vring->msix_name, 256, "x_vdpa[%s]-%d\n",
+		 pci_name(pci_dev), idx);
+	irq = pci_irq_vector(pci_dev, idx);
+	rc = devm_request_irq(&pci_dev->dev, irq, vring_intr_handler, 0,
+			      vring->msix_name, vring);
+	if (rc)
+		pci_err(pci_dev,
+			"devm_request_irq failed for vring %d, rc %d\n",
+			idx, rc);
+	else
+		vring->irq = irq;
+
+	return rc;
+}
+
+static int delete_vring(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
+{
+	struct efx_vring_dyn_cfg vring_dyn_cfg;
+	int rc;
+
+	if (!(vdpa_nic->vring[idx].vring_state & EF100_VRING_CREATED))
+		return 0;
+
+	rc = efx_vdpa_vring_destroy(vdpa_nic->vring[idx].vring_ctx,
+				    &vring_dyn_cfg);
+	if (rc)
+		dev_err(&vdpa_nic->vdpa_dev.dev,
+			"%s: delete vring failed index:%u, err:%d\n",
+			__func__, idx, rc);
+	vdpa_nic->vring[idx].last_avail_idx = vring_dyn_cfg.avail_idx;
+	vdpa_nic->vring[idx].last_used_idx = vring_dyn_cfg.used_idx;
+	vdpa_nic->vring[idx].vring_state &= ~EF100_VRING_CREATED;
+
+	irq_vring_fini(vdpa_nic, idx);
+
+	return rc;
+}
+
+static void ef100_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx)
+{
+	struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+	u32 idx_val;
+
+	if (is_qid_invalid(vdpa_nic, idx, __func__))
+		return;
+
+	if (!(vdpa_nic->vring[idx].vring_state & EF100_VRING_CREATED))
+		return;
+
+	idx_val = idx;
+	_efx_writed(vdpa_nic->efx, cpu_to_le32(idx_val),
+		    vdpa_nic->vring[idx].doorbell_offset);
+}
+
+static bool can_create_vring(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
+{
+	if (vdpa_nic->vring[idx].vring_state == EF100_VRING_CONFIGURED &&
+	    vdpa_nic->status & VIRTIO_CONFIG_S_DRIVER_OK &&
+	    !(vdpa_nic->vring[idx].vring_state & EF100_VRING_CREATED))
+		return true;
+
+	return false;
+}
+
+static int create_vring(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
+{
+	struct efx_vring_dyn_cfg vring_dyn_cfg;
+	struct efx_vring_cfg vring_cfg;
+	int rc;
+
+	rc = irq_vring_init(vdpa_nic, idx);
+	if (rc) {
+		dev_err(&vdpa_nic->vdpa_dev.dev,
+			"%s: irq_vring_init failed. index:%u, err:%d\n",
+			__func__, idx, rc);
+		return rc;
+	}
+	vring_cfg.desc = vdpa_nic->vring[idx].desc;
+	vring_cfg.avail = vdpa_nic->vring[idx].avail;
+	vring_cfg.used = vdpa_nic->vring[idx].used;
+	vring_cfg.size = vdpa_nic->vring[idx].size;
+	vring_cfg.features = vdpa_nic->features;
+	vring_cfg.msix_vector = idx;
+	vring_dyn_cfg.avail_idx = vdpa_nic->vring[idx].last_avail_idx;
+	vring_dyn_cfg.used_idx = vdpa_nic->vring[idx].last_used_idx;
+
+	rc = efx_vdpa_vring_create(vdpa_nic->vring[idx].vring_ctx,
+				   &vring_cfg, &vring_dyn_cfg);
+	if (rc) {
+		dev_err(&vdpa_nic->vdpa_dev.dev,
+			"%s: vring_create failed index:%u, err:%d\n",
+			__func__, idx, rc);
+		goto err_vring_create;
+	}
+	vdpa_nic->vring[idx].vring_state |= EF100_VRING_CREATED;
+
+	/* A VQ kick allows the device to read the avail_idx, which will be
+	 * required at the destination after live migration.
+	 */
+	ef100_vdpa_kick_vq(&vdpa_nic->vdpa_dev, idx);
+
+	return 0;
+
+err_vring_create:
+	irq_vring_fini(vdpa_nic, idx);
+	return rc;
+}
+
+static void reset_vring(struct ef100_vdpa_nic *vdpa_nic, u16 idx)
+{
+	delete_vring(vdpa_nic, idx);
+	vdpa_nic->vring[idx].vring_type = EF100_VDPA_VQ_NTYPES;
+	vdpa_nic->vring[idx].vring_state = 0;
+	vdpa_nic->vring[idx].last_avail_idx = 0;
+	vdpa_nic->vring[idx].last_used_idx = 0;
+}
+
+static void ef100_reset_vdpa_device(struct ef100_vdpa_nic *vdpa_nic)
+{
+	int i;
+
+	WARN_ON(!mutex_is_locked(&vdpa_nic->lock));
+
+	if (!vdpa_nic->status)
+		return;
+
+	vdpa_nic->vdpa_state = EF100_VDPA_STATE_INITIALIZED;
+	vdpa_nic->status = 0;
+	vdpa_nic->features = 0;
+	for (i = 0; i < (vdpa_nic->max_queue_pairs * 2); i++)
+		reset_vring(vdpa_nic, i);
+	ef100_vdpa_irq_vectors_free(vdpa_nic->efx->pci_dev);
+}
+
+/* May be called under the rtnl lock */
+int ef100_vdpa_reset(struct vdpa_device *vdev)
+{
+	struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+
+	/* vdpa device can be deleted anytime but the bar_config
+	 * could still be vdpa and hence efx->state would be STATE_VDPA.
+	 * Accordingly, ensure vdpa device exists before reset handling
+	 */
+	if (!vdpa_nic)
+		return -ENODEV;
+
+	mutex_lock(&vdpa_nic->lock);
+	ef100_reset_vdpa_device(vdpa_nic);
+	mutex_unlock(&vdpa_nic->lock);
+	return 0;
+}
+
+static int start_vdpa_device(struct ef100_vdpa_nic *vdpa_nic)
+{
+	struct efx_nic *efx = vdpa_nic->efx;
+	struct ef100_nic_data *nic_data;
+	int i, j;
+	int rc;
+
+	nic_data = efx->nic_data;
+	rc = ef100_vdpa_irq_vectors_alloc(efx->pci_dev,
+					  vdpa_nic->max_queue_pairs * 2);
+	if (rc < 0) {
+		pci_err(efx->pci_dev,
+			"vDPA IRQ alloc failed for vf: %u err:%d\n",
+			nic_data->vf_index, rc);
+		return rc;
+	}
+
+	for (i = 0; i < (vdpa_nic->max_queue_pairs * 2); i++) {
+		if (can_create_vring(vdpa_nic, i)) {
+			rc = create_vring(vdpa_nic, i);
+			if (rc)
+				goto clear_vring;
+		}
+	}
+
+	vdpa_nic->vdpa_state = EF100_VDPA_STATE_STARTED;
+	return 0;
+
+clear_vring:
+	for (j = 0; j < i; j++)
+		delete_vring(vdpa_nic, j);
+
+	ef100_vdpa_irq_vectors_free(efx->pci_dev);
+	return rc;
+}
+
 static int ef100_vdpa_set_vq_address(struct vdpa_device *vdev,
 				     u16 idx, u64 desc_area, u64 driver_area,
 				     u64 device_area)
@@ -144,22 +361,6 @@ static void ef100_vdpa_set_vq_num(struct vdpa_device *vdev, u16 idx, u32 num)
 	mutex_unlock(&vdpa_nic->lock);
 }
 
-static void ef100_vdpa_kick_vq(struct vdpa_device *vdev, u16 idx)
-{
-	struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
-	u32 idx_val;
-
-	if (is_qid_invalid(vdpa_nic, idx, __func__))
-		return;
-
-	if (!(vdpa_nic->vring[idx].vring_state & EF100_VRING_CREATED))
-		return;
-
-	idx_val = idx;
-	_efx_writed(vdpa_nic->efx, cpu_to_le32(idx_val),
-		    vdpa_nic->vring[idx].doorbell_offset);
-}
-
 static void ef100_vdpa_set_vq_cb(struct vdpa_device *vdev, u16 idx,
 				 struct vdpa_callback *cb)
 {
@@ -176,6 +377,7 @@ static void ef100_vdpa_set_vq_ready(struct vdpa_device *vdev, u16 idx,
 				    bool ready)
 {
 	struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+	int rc;
 
 	if (is_qid_invalid(vdpa_nic, idx, __func__))
 		return;
@@ -184,9 +386,21 @@ static void ef100_vdpa_set_vq_ready(struct vdpa_device *vdev, u16 idx,
 	if (ready) {
 		vdpa_nic->vring[idx].vring_state |=
 					EF100_VRING_READY_CONFIGURED;
+		if (vdpa_nic->vdpa_state == EF100_VDPA_STATE_STARTED &&
+		    can_create_vring(vdpa_nic, idx)) {
+			rc = create_vring(vdpa_nic, idx);
+			if (rc)
+				/* Rollback ready configuration
+				 * So that the above layer driver
+				 * can make another attempt to set ready
+				 */
+				vdpa_nic->vring[idx].vring_state &=
+					~EF100_VRING_READY_CONFIGURED;
+		}
 	} else {
 		vdpa_nic->vring[idx].vring_state &=
 					~EF100_VRING_READY_CONFIGURED;
+		delete_vring(vdpa_nic, idx);
 	}
 	mutex_unlock(&vdpa_nic->lock);
 }
@@ -296,6 +510,12 @@ static u64 ef100_vdpa_get_device_features(struct vdpa_device *vdev)
 	}
 
 	features |= BIT_ULL(VIRTIO_NET_F_MAC);
+	/* As QEMU SVQ doesn't implement the following features,
+	 * masking them off to allow Live Migration
+	 */
+	features &= ~BIT_ULL(VIRTIO_F_IN_ORDER);
+	features &= ~BIT_ULL(VIRTIO_F_ORDER_PLATFORM);
+
 	return features;
 }
 
@@ -356,6 +576,77 @@ static u32 ef100_vdpa_get_vendor_id(struct vdpa_device *vdev)
 	return EF100_VDPA_VENDOR_ID;
 }
 
+static u8 ef100_vdpa_get_status(struct vdpa_device *vdev)
+{
+	struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+	u8 status;
+
+	mutex_lock(&vdpa_nic->lock);
+	status = vdpa_nic->status;
+	mutex_unlock(&vdpa_nic->lock);
+	return status;
+}
+
+static void ef100_vdpa_set_status(struct vdpa_device *vdev, u8 status)
+{
+	struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+	u8 new_status;
+	int rc;
+
+	mutex_lock(&vdpa_nic->lock);
+	if (!status) {
+		dev_info(&vdev->dev,
+			 "%s: Status received is 0. Device reset being done\n",
+			 __func__);
+		ef100_reset_vdpa_device(vdpa_nic);
+		goto unlock_return;
+	}
+	new_status = status & ~vdpa_nic->status;
+	if (new_status == 0) {
+		dev_info(&vdev->dev,
+			 "%s: New status same as current status\n", __func__);
+		goto unlock_return;
+	}
+	if (new_status & VIRTIO_CONFIG_S_FAILED) {
+		ef100_reset_vdpa_device(vdpa_nic);
+		goto unlock_return;
+	}
+
+	if (new_status & VIRTIO_CONFIG_S_ACKNOWLEDGE) {
+		vdpa_nic->status |= VIRTIO_CONFIG_S_ACKNOWLEDGE;
+		new_status &= ~VIRTIO_CONFIG_S_ACKNOWLEDGE;
+	}
+	if (new_status & VIRTIO_CONFIG_S_DRIVER) {
+		vdpa_nic->status |= VIRTIO_CONFIG_S_DRIVER;
+		new_status &= ~VIRTIO_CONFIG_S_DRIVER;
+	}
+	if (new_status & VIRTIO_CONFIG_S_FEATURES_OK) {
+		vdpa_nic->status |= VIRTIO_CONFIG_S_FEATURES_OK;
+		vdpa_nic->vdpa_state = EF100_VDPA_STATE_NEGOTIATED;
+		new_status &= ~VIRTIO_CONFIG_S_FEATURES_OK;
+	}
+	if (new_status & VIRTIO_CONFIG_S_DRIVER_OK &&
+	    vdpa_nic->vdpa_state == EF100_VDPA_STATE_NEGOTIATED) {
+		vdpa_nic->status |= VIRTIO_CONFIG_S_DRIVER_OK;
+		rc = start_vdpa_device(vdpa_nic);
+		if (rc) {
+			dev_err(&vdpa_nic->vdpa_dev.dev,
+				"%s: vDPA device failed:%d\n", __func__, rc);
+			vdpa_nic->status &= ~VIRTIO_CONFIG_S_DRIVER_OK;
+			goto unlock_return;
+		}
+		new_status &= ~VIRTIO_CONFIG_S_DRIVER_OK;
+	}
+	if (new_status) {
+		dev_warn(&vdev->dev,
+			 "%s: Mismatch Status: %x & State: %u\n",
+			 __func__, new_status, vdpa_nic->vdpa_state);
+	}
+
+unlock_return:
+	mutex_unlock(&vdpa_nic->lock);
+}
+
 static size_t ef100_vdpa_get_config_size(struct vdpa_device *vdev)
 {
 	return sizeof(struct virtio_net_config);
@@ -393,6 +684,20 @@ static void ef100_vdpa_set_config(struct vdpa_device *vdev, unsigned int offset,
 		vdpa_nic->mac_configured = true;
 }
 
+static int ef100_vdpa_suspend(struct vdpa_device *vdev)
+{
+	struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+	int i, rc;
+
+	mutex_lock(&vdpa_nic->lock);
+	for (i = 0; i < (vdpa_nic->max_queue_pairs * 2); i++) {
+		rc = delete_vring(vdpa_nic, i);
+		if (rc)
+			break;
+	}
+	mutex_unlock(&vdpa_nic->lock);
+	return rc;
+}
 static void ef100_vdpa_free(struct vdpa_device *vdev)
 {
 	struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
@@ -428,9 +733,13 @@ const struct vdpa_config_ops ef100_vdpa_config_ops = {
 	.get_vq_num_max      = ef100_vdpa_get_vq_num_max,
 	.get_device_id	     = ef100_vdpa_get_device_id,
 	.get_vendor_id	     = ef100_vdpa_get_vendor_id,
+	.get_status	     = ef100_vdpa_get_status,
+	.set_status	     = ef100_vdpa_set_status,
+	.reset               = ef100_vdpa_reset,
 	.get_config_size     = ef100_vdpa_get_config_size,
 	.get_config	     = ef100_vdpa_get_config,
 	.set_config	     = ef100_vdpa_set_config,
 	.get_generation      = NULL,
+	.suspend	     = ef100_vdpa_suspend,
 	.free	             = ef100_vdpa_free,
 };
-- 
2.30.1

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